14.4 Conditional Tests

If you write tests directly from the specification before you've written the code, the tests are expected to fail. You can include some of your tests inside a TODO block to include them for test count but denote them as unavailable at the same time. For example, suppose you haven't taught your horses how to talk yet:

 use Test::More 'no_plan'; use_ok("Horse"); my $tv_horse = Horse->named("Mr. Ed"); TODO: {   local $TODO = "haven't taught Horses to talk yet";   can_ok($tv_horse, "talk");  # he can talk! } is($tv_horse->name, "Mr. Ed", "I am Mr. Ed!"); 

Here, the test is inside a TODO block, setting a package $TODO variable with the reason why the items are unfinished : ^[13]

^[13] TODO tests require Test::Harness Version 2.0 or later, which comes with Perl 5.8, but in earlier releases, they have to be installed from the CPAN .

 ok 1 - use Horse; not ok 2 - Horse->can('talk') # TODO haven't taught Horses to talk yet #     Failed (TODO) test (1.t at line 7) #     Horse->can('talk') failed ok 3 - I am Mr. Ed! 1..3 

Note that the TODO test counts toward the total number of tests. Also note that the message about why the test is a TODO test is displayed as a comment. The comment has a special form, noted by the test harness, so you will see it during a make test run.

You can have multiple TODO tests in a given block, but only one reason per block, so it's best to group things that are related but use different blocks for different reasons.